I'm wondering WHY can't the caching mode cannot be obtained by the kernel?
- Is it because the kernel is trying to inquire about the cache on a physical
disk, and the sda and sdb it sees are actually logical drives, and the
situation is perfectly normal?
- Or is it something wrong with the card?
- Or maybe there is no support for such operation in the megaraid
driver?
- Is it something else even? Do I need to do something more to find
out?

The message is simply a little worrying for me, because I don't understand why
the "asking" fails.